Palo Alto , CA -LRB- CNN -RRB- -- It does not make for pleasant dinner conversation . But we have a global sanitation crisis . More than 40 % of the world 's population does not have access to a toilet . These 2.6 billion people , most living in low - and middle-income countries in Asia and Africa , face the daily challenge of finding a bush , train track or empty lot where they can urinate and defecate in relative privacy .

Between 1990 and 2008 , the share of the world 's population that had access to basic sanitation increased only 7 % , to 61 % of the world 's citizens . In many developing countries , mobile phone penetration is expanding at a faster rate than sanitation . In Tanzania , for example , half the country 's citizens have mobile phones , but only 24 % use an improved sanitation facility .

Saturday marks the 10th anniversary of World Toilet Day , a day set aside not simply as a celebration of this most venerable and useful of technologies , but as a way to draw attention to the crisis and some possible solutions .

This sanitation crisis is not only an affront to dignity . It results in the release of hundreds of tons of feces and urine each day directly into rivers , lakes , landfills and oceans , creating an immense human and environmental health hazard . Every day more than 4,000 young children die from sanitation-related illness . Fully half of the hospital beds in the developing world are occupied by people whose ailments can be traced to poor sanitation .

A small but dedicated community that includes governments , NGOs , donors and research institutions is working to expand access to basic sanitation services in developing countries . They employ a range of innovative strategies , including `` naming and shaming '' community members who defecate in the open , constructing public toilets operated by entrepreneurs , and providing subsidies to help households build their own facilities .

In most cases these sanitation champions promote or deliver `` on-site '' services such as a pit latrine or a toilet with septic tank . These facilities capture feces and urine in a chamber under or next to the users ' dwelling . When adopted on a wide scale and maintained properly , these solutions can dramatically improve household and environmental sanitation .

On-site solutions are also popular because they cost less to build , and require much lower volumes of water than a conventional sewer system . In addition , some on-site sanitation facilities allow for the possibility of generating biogas for cooking and lighting , and for re-using composted excreta as fertilizer for agriculture .

Given all these benefits from improved sanitation , why has it proven so difficult to expand access to this essential service ?

One answer may be that the kinds of sanitation facilities offered to developing country households are not terribly appealing . As sanitation guru Professor Sandy Cairncross of the London School of Hygiene & Tropical Medicine noted two decades ago , `` For those accustomed to a contemplative squat in the open air in the cool of the early morning , who among them would choose a dark , damp , smelly and possibly precarious cubicle ? ''

Efforts to keep sanitation as low-cost as possible may also be part of the problem , at least for some consumers . Researchers from the University of North Carolina-Chapel Hill working recently in Southeast Asia found that households prefer and are willing to pay for higher quality toilets , particularly when they are marketed as a symbol of prestige and modernity , rather than just a preventive health measure .

This shift toward aspirational marketing is one important step toward generating greater household demand for improved sanitation services . In order to turn the tide on the global sanitation crisis , however , efforts are also needed to develop models for low - and no-water sanitation systems at scale , models to which municipal and national governments themselves can aspire .

In cities across the United States , the transition from outhouses and privies to sanitary sewers occurred more than a century ago , when metropolitan populations numbered in the tens or hundreds of thousands . Today there are more than a dozen cities in developing countries that have at least 5 million inhabitants , most of whom rely on latrines or toilets with septic tanks .

Municipalities with limited resources struggle to regulate , much less manage , the emptying and safe disposal of sludge from these facilities . It is estimated that only 15 % of domestic waste in developing countries undergoes any form of treatment before being discharged to the environment .

In the United States , our prevailing urban sanitation model has changed little in the past century , with the typical American flushing more than 12,000 liters of potable water down the sewer every year . Despite declining per capita fresh water availability , increasing frequency of municipal water rationing and the need to replace a large share of the country 's aging wastewater infrastructure , there is little discussion as to how domestically we might transition to a sustainable sanitation future that reduces freshwater requirements and lowers energy costs .

Waterless and composting toilets are niche technologies , marketed to `` ultra-green '' consumers and those living in remote locations . Indeed , the recycling of grey water , even for nonpotable uses such as watering landscapes , is still controversial in many places .

Certainly , most people do n't want to talk about poop , much less debate whether and how it might be recycled in their communities . But it is precisely this debate that is needed . We need to trigger sanitation innovations that can benefit citizens of wealthy and poor countries , and also instigate systems that help protect the resource base they depend on for development .

Would n't that be something to celebrate ?

The opinions expressed in this commentary are solely those of Jenna Davis .

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Jenna Davis : 2.6 billion people do not have access to toilets , a global sanitation crisis

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Every day more than 4,000 children die from sanitation-related illness , she says

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Davis : A dedicated community is working to expand access to basic sanitation services

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In the U.S. , the prevailing urban sanitation model has changed little in 100 years , she says